<!DOCTYPE html>
<html>
	<head>
		<meta charset="utf-8">
		<title></title>
	</head>
	<body>
		<script>
			var i = 0;
			document.onclick = function() {
				i++;
				switch (i) {
					case
					1:
						alert('你好同学');
						break;
					case
					2:
						alert('吃饭了吗同学')
						break;
					case
					3:
						alert('你吃饱了吗');
						break;
					case
					4:
						alert('我是实训一的');
						break;
				}
			}
		</script>
	</body>
</html>